ABSTRACT
Wilm's tumor, which is the most mommon renal tumor in childhood, has rarely been reported in adult. Diagnosis of Wilm's tumor in an adult is more apt to be accidental and is almost never suspected in the adult until discovered at operation or necropsy. Recently, we experienced a caseof Wilm's tumor in 20-year-old female patient with chief complaints of right flank pain and he maturia for two months. Renal angiogram revealed a huge renal mass replacing the upper portion of the right kidney. Nephrectomy was done under the impression of renal tumor. Grossly, the tumor was rather soft and relatively well circumscribed, measuring 13 x 8.3 cm in dimension with adhesion to renal capsule and perirenal adipose tissue. The cut surfaces revealed grayish brown in color with areas of multifocal necrosis and hemorrhage. Histologically, the tumor was composed of mainly ovoid or polygonal shaped undifferentiated blastemal cells with large areas of necrosis.